The Complete Book on Meat Processing and Preservation with Packaging Technology

Published: 2005Publisher: Asia Pacific Business Press Inc.
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Meat was originally processed to preserve it, but since the various procedures cause so many changes in texture and flavour it is also a means of adding variety to the diet. Processing also provides scope to mix the less desirable parts of the carcass with lean meat and in addition is a means of extending meat supplies by including other foodstuffs such as cereal in the product. Food preservation is a method of maintaining foods at a desired level of properties or nature for their maximum benefits. Preservation usually involves preventing the growth of bacteria, yeasts, fungi, and other micro organisms (although some methods work by introducing bacteria, or fungi to the food), as well as retarding the oxidation of fats which cause rancidity. Today, meat is processed with salt, colour fixing ingredients, and seasonings in order to impart desired palatability traits to intact and comminuted meat products. Products intermediate to these categories are sectioned, or chunked and formed meats. There are various methods for the preservation of meat; curing, dry curing, smoking, canning, freezing dehydration, fat extraction (wet or steam rendering), etc. Meat curing agents include sodium chloride, nitrite, ascorbate or erythorbate and possibly sodium phosphate, sucrose, dextrose, or corn syrup and seasonings. The salt content of processed meats varies 1 to 12%, according to the type of product. Many intact and comminuted, cured meat products are smoked to impart a desirable smoked flavour and colour. The smoking process many also include a drying or cooking cycle, depending on the product. Canned meats may be processed to be commercially sterile or semi preserved. The objective of commercial sterilization is to destroy all harmful bacteria or bacteria that may cause spoilage of the product under normal unrefrigerated storage. However, the process does not kill the spores of all heat resistant bacteria. Frozen meat can be kept at low temperatures for many months. Freezing and subsequent thawing produce changes in the structure of meat that affect its physical properties. If meat is frozen very rapidly at low temperatures, the ice crystals are small and form within the fibers. The drip loss upon thawing is generally greater in slow frozen than in quick frozen meat. Freeze drying meat extends shelf life and reduces weight. The meat is readily defrosted by immersing in water before cooking. Under optimum processing and storage conditions, reconstituted meats have acceptable flavour, colour, texture and nutrient retention.
The meat packing industry handles the slaughtering, processing, packaging, and distribution of animals such as cattle, pigs, sheep and other livestock. The basic purpose of packaging is to protect meat and meat products from undesirable impacts on quality including microbiological and physio chemical alterations. Packaging protects foodstuffs during processing, storage and distribution from contamination by dirt (by contact with surfaces and hands), microorganisms (bacteria, moulds, and yeasts), parasites (mainly insects), toxic substances (chemicals), influences affecting colour, smell and taste (off odour, light, oxygen), loss or uptake of moisture. As such, due to the recent up gradation of preservation techniques, the preservation industry is also growing almost at the same rate as the food industry which is about 10 to 12% per year.
Some of the fundamentals of the book are meat product, simultaneous flavouring and tenderizing, synthetic flavouring, preservation: moisture retention and surface protection, antimicrobial treatment, antioxidant application to freeze dried meats, packaging and handling for storage and transportation, continuous steam cooking of ground meat, activators of natural proteolytic enzymes, isotonic enzyme solution with specific activity, inactivation of enzymes with high pressure, etc.
The origin of meat processing is lost in antiquity but probably began when primitive humans first learned that salt is an effective preservative and that cooking prolongs the keeping quality of fresh meat. This book includes the processing of fresh meats, the different curing agents, method of curing, smoking and manufacturing of various meat products such as sausages, canned meat, cured and smoked meats etc. The book is very useful for entrepreneurs, technocrats and those who want to venture in to this field.

Sample Chapters

Meat, an excellent source of protein, iron and B vitamins, was processed
as early as prehistoric times, probably by drying in the sun and later by
smoking and drying over wood fires. Homer, in 850 B.C., recorded procedures for
smoking and salting of meat. The purpose of meat processing was to prepare
products that could be stored for considerable time periods at ambient
temperatures. The high salt concentration that was essential for meat
preservation before the widespread use of refrigeration is no longer needed or
desired. Today, meat is processed with salt, colour-fixing ingredients, and
seasonings in order to impart desired palatability traits to intact and
comminuted meat products. Intact meat products include bacon, corned beef, ham,
smoked butt and pork hocks. Comminuted meat products include all types of
sausage items. Products intermediate to these categories are sectioned, or
chunked and formed meats.

CURING

Meat-curing agents include Sodium Chloride, Nitrite, Ascorbate or
Erythorbate and possibly Sodium Phosphate, Sucrose, Dextrose, or Corn Syrup and
seasonings. The salt content of processed meats varies 1-12%, according to the
type of product. Salt is used for flavour, preservation and extraction of my
myofibrillar protein, whereas nitrite promotes colour development, flavour and
preservation by inhibiting the growth of microorganisms and fat oxidation.
Erythorbate acts as a colour stabilizer, reduces fat oxidation and inhibits
undesirable nitrite reactions. Phosphates facilitate myofibrillar protein
extraction, inhibit fat oxidation and improve colour development sugars and
seasonings are used principally for flavour.

COLOUR CHANGES

The most obvious characteristic of cured meats is the development of the
characteristic pink colour on heat processing compared to the brown colour of
uncured cooked meat. The colour result from a reaction between the heme protein
myoglobin and nitrite. Other heme protein, such as hemoglobin and cytochromes,
react similarly but are present in much smaller amounts.

Only 20-30 ppm of nitrite are required for colour development but higher
concentration are needed to maintain colour.

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Current regulations permit the use of Sodium and Potassium Nitrates and
Nitrites in meat and poultry products. However, the status of these chemicals as
food additives is in doubt because of tests indicating the possibility of
carcinogenic properties. Nitrates are generally no longer
used except in some dry cured products and are not permitted in pumped
bacon. Nitrites are limited to 120 ppm ingoing in pumped bacon and must be
accompanied by Sodium Ascorbate or Erythorbate at no less than 550 ppm. Neither
Nitrites nor Nitrates are permitted in baby foods.

PICKLE CURING

Pickle-cured
hams are generally pumped before being placed in the curing vat, that is,
pickling solution (pickle) is injected in to the ham in order to hasten
diffusion of the curing ingredients throughout the ham. For short cures, hams
and pork shoulders are generally artery-or stitch-pumped. In artery pumping, a
special needle is inserted into the end of the exposed artery and pickling
solution (about 15 wt% of the ham depending on product and process) is pumped
into the vascular system. Pump pressures are 340-380 kpa (3.4-3.8 atm.)

In stitch or spray pumping, the brine enters the meat through numerous
perforations in the walls of hollow needles. Most hams and bacon cured in the
United States are injected with automatic, multineedle injectors through a
number of fine hollow-stemmed needles arranged in a bank which automatically
moves the needles into the product as it moves on conveyor belts. The amount of
water added to cured meat products is determined by government regulations.
Cured and smoked hams and bacon shall not contain more than uncured hams. Canned
cured pork products may not contain more than 8% added water, whereas noncanned
cured products may contain added water up 10% of the uncured product. To
accelerate the distribution of the pickling solution within the product and
improve cure uniformity, boneless hams may be tumbled or massaged after
injection.

DRY CURING

This is an older method in which curing agents are rubbed in dry form
over the surface of the cut of meat. The cuts are then stored and allowed to
cure. For large cuts, the cure must be applied several times. Dry curing is now
used only on specialty items such as country-cured hams and bacons.

COMMINUTION

Comminuted meat may be cured or a fresh product. The degree of
comminution varies considerably from one product to another. Sectioned or
chunked and formed products may be composed of particles that weigh more than
450g each, whereas finely comminuted meats are chopped to a paste like texture
of very small particles. Comminution equipment includes grinders, silent
cutters, emulsion mills and flaking machines. In addition to comminution the
meat is blended with other ingredients. Blenders, mixers, tumblers and massagers
are used to subject the meat protein to mechanical action in the presence of
salt. This causes the salt to extract the principal myofibrillar protein,
myosin, from the muscle. The extracted myosin gels when the comminuted meat is
heated to form a matrix, which entraps water and fat and binds the meat
particles to each other.

Comminution reduces the raw meat material to small meat pieces, chunks,
chips or slices. Sausages are comminuted, seasoned meat products that may also
be cured, smoked, molded heat-processed. They are classified according to the
processing methods used for their manufacture.

Large particles or chunks of meat can be massaged or tumbled in the
presence of salt and phosphate (usually Sodium tripolyphosphate or
hexametaphosphate) to extract salt-soluble proteins that form a tacky exudates
which acts as a heat-set glue to bind the chunks of meat together after cooking.
This method is used to prepare chunked and formed hams, roasts, and steaks. This
is a growing area of production because it permits the manufacture of products
that have the composition, shape and size preferred by the consumer.

SMOKING

Many intact and comminuted, cured meat products are smoked to impart a
desirable smoked flavour and colour. The smoking process many also include a
drying or cooking cycle, depending on the product.

The smoking process imparts a characteristic flavour to product. In
addition, some phenolic compounds present in smoke provide protection from fat
oxidation. Further protection is provided by the bacteriostatic effect of smoke
components along with the drying effect that inhibits bacterial growth on the
dried surface.

Modern processes use forced-air smoking chambers with close control of
time, temperature and humidity. The processing cycle many include predrying,
smoking, cooking, drying and cooling. Smoke is generated by electrical
smoke-heated generators, which offer close control over temperatures and hence
smoke composition or liquid smoke may be used as an atomized spray or
regenerated smoke. Smoking chambers are designed for batch or continuous
processes.

Oil or water-based liquid smoke can be added directly to the products as
a flavouring in lieu of the smoking process. Oil-based liquid smokes are used
when the product is sensitive to the low PH of water-based liquid
smokes and to ensure penetration of the smoke components into the fat phase.

CANNING

Canned meats may be processed to be commercially sterile or
semipreserved. The objective of commercial sterilization is to destroy all
harmful bacteria or bacteria that may cause spoilage of the product under normal
unrefrigerated storage. However, the process does not kill the spores of all
heat-resistant bacteria.

Therefore, it is essential to cool the cans rapidly after processing and
avoid storage above 35Â°C. The most persistent type of bacteria are sporeforming
organisms. The common vegetative and nonsporeforming pathogenic bacteria are
killed with adequate processing and are of little or no importance in spoilage.

The amount of heat, time and temperature required for a given degree of
sterility depends upon the nature of the product, the PH curing
salts, shape and size of the can and the type of heat processing retort used.
Some products are packed into the can hot and others cold. Hot filling
eliminates the need to apply a vacuum during can closure. The vacuum is
necessary to avoid excessive strain on the can and its seams during processing
and to minimize oxidative spoilage of the product.

Semipreserved or pasteurized products depend on curing and chilled
storage for their preservation.

FREEZING

Frozen meat can be kept at low temperatures for many months. Freezing and
subsequent thawing produce changes in the structure of meat that affect its
physical properties. If meat is frozen very rapidly at low temperatures, the ice
crystals are small and form within the fibers. The drip loss upon thawing is
generally greater in slow-frozen than in quick-frozen meat. The rate of freezing
is determined largely by temperature, freezing system and shape of the cut.
Holding a quick-frozen product at high and fluctuating temperatures encourages
the growth of ice crystals and protein denaturation and the advantage of low
drip loss from rapid freezing is lost. The amount of drip in meat is further
affected by temperature and length of storage, meat surface, thawing rate and
the physiological condition of the muscle at slaughter and

Packaged frozen meat cuts are sold in the retail markets to a limited
extent and stored both consumer in home freezers. Beef retains good quality for
a year or more and pork for six months if properly packaged and stored at- 18
to-23Â°C. Freezer burn or dehydration and discolouration can be prevented with
packaging systems that cling closely to the product surface and restrict
movement of moisture from the product surface and the diffusion of oxygen into
the product.

DEHYDRATION

Freeze-Drying

Freezing drying of meat results in a product with a sponge like
appearance, practically devoid of moisture but resembling the original product.
The composition and type of meat influence the acceptability and stability of
freeze-dried meat.

Freeze-drying meat extends shelf life and reduces weight. The meat is
readily defrosted by immersing in water before cooking. Under optimum processing
and storage conditions, reconstituted meats have acceptable flavour, colour,
texture and nutrient retention.

Freeze-drying
does not entirely eliminate changes in meat products during processing and
storage. Enzymic changes are reduced but not completely eliminated.
Deteriorative changes include some loss of vitamins, protein denaturation,
browning and fat rancidity. To avoid deterioration it is essential that the
product is packaged under an inert gas, in moisture, gas and light impermeable.

AIR-DRYING

Precooked comminuted lean meat is dried in a forced-air rotary or tunnel
dryer to less than 10% moisture for use as an ingredient in dried soups and
stews. The dried product is often compressed to reduce its volume to about one
third of the fresh meat volume for shipment.

BY-PRODUCTS

By-products in the meat-packing industry represent a substantial part of
the sales value of the production derived from the slaughter of animals.
By-products include variety meats, edible and inedible fats and hides and other
inedibles. The value of meat or by-products depends upon the species and age of
the animal, degree of finish and price.

Approved portions of the carcasses of clean, sound meat animals yield
edible fats including lard (from swine), edible tallow (from cattle and sheep)
and related products such as oleo stock. These may be consumed in the form of
shortening for baking and similar food applications, or as frying fats.

Inedible fats are used widely in animal feeds and for other industrial
uses. The principal products of this type are inedible tallow and grease.

The efficient utilization of by-product is essential for the economic
operation of a packing plant.

FAT EXTRACTION

Wet Or Steam Rendering

In this procedure, the raw materials are cooked in a closed vertical tank
under pressure by direct steam injection, typically at 380-500 kPa (3.8-4.9 atm)
for 3.6h. The tallow is drawn off from the top of the vessel after it has been
allowed to settle for several hours. The process was used mostly for hard raw
materials such as bones but is being replaced by modern methods.

Dry rendering

Both
batch and continuous processes are available for dry rendering. The material is
heated in a horizontal steam-jacketed cooking vessel equipped with rotating arms
to agitate the material. The moisture driven off is usually vented through a
condenser to recover heat and control atmospheric pollution. At the completion
of the rendering operation the fat is separated from the cooked material
(tankage) by basket centrifuges or expellers in batch processes and by
continuous centrifugation in continuous processes. Bones are coarsely crushed
before rendering. Viscera should be washed of their contents and should be
rendered with minimum delay to maximize tallow quality in terms of colour and
free fatty acid content.

Low Temperature Rendering

High-quality fats are produced by semibatch or continuous processes and
the defatted residues may be used in some processed meat products. The raw
material is first comminuted and then heated to about 45-50Â°C. The fat is then
separated by centrifugation.

Fat Processing

After rendering, the fat is usually further processed outside the
meat-processing plant. Depending on the desired product fat, the fats may be
hydrogenated, bleached, deodorized, plasticized, interesterified or
fractionated.

Unsaturation in the fatty acids is eliminated by hydrogenation in the
presence of a catalyst under carefully controlled temperature, pressure and
mixing conditions. Hydrogenation raises the melting point of the fat and
modifies the plastic rang.

Bleaching can be achieved by liquid extraction, hydrogenation or
treatment with absorbents.

Odiferous substances are removed by steam-stripping at 150-250Â°C under
high vacuum. Free fatty acids also are removed by this process which yield a
bland fat with a high smoke point.

Plasticizing imparts desirable textural properties to fats. The process
often involves chilling the fat through its melting range to promote the
formation of crystal nuclei, followed by mechanical working to inhibit the
growth of large fat crystals. The fat is then tempered by holding it for a
certain time at and appropriate temperature. Tempering inhibits subsequent
crystal growth because of fluctuating temperatures below the fatâ€™s melting
point.

Interesterification
rearranges the distribution of fatty acids on the glycerol moiety of the fat
molecule. It is used particularly in shorting manufacture where it imparts
desirable baking properties to the fat.

Fractionation involves separating animal fat by fractional
crystallization into oils and fats which have specific applications.

CHAPTER 3

FLAVOUR AND TENDRENES

Typical
ripe flavour overtones are missing in unaged meat. True beef flavour, for
example, is fully developed after at least one week of aging. At the same time,
as the bouquet develops the meat becomes more ana more tender. Ripe flavour
develops during the normal aging process at low temperatures, which, as
described in the previous chapter, is a slow and wasteful process.

As the methods in this chapter describe, natural flavour development and
tenderization can be accelerated considerably by fungal and bacterial
proteolytic enzymes, the process being complete in only a few days. About by a
combined action of various flavouring and tenderizing agents.

SINULTANEOUS
FLAVOURING AND TENDERZING ACTION OF MOLDS AND BACTERIA

A
mold species, Thammidium elegans, seems to be quite useful for flavour
development and tenderizing of meats, it imparts a black walnut taste to the
meat which is characteristic of carefully and properly aged meat having rich,
mellow flavour. The bacteria Pseudomonas and Achromobacter may similarly be
applied. Aspergillus nigar, on the other hand, is said to enhance the flvour of
meats without tenderizing; tenderizing is accomplished by prerigor mortis water
injection with the mold.

Action Of Thammidium Elegans

Williams;
has found that beef can be properly ripened and tendered, with improved colour,
in approximately 48 hr if, after rigor mortis, the beef is introduced at a
temperature of approximately 35Â°F into the meat-ripening space having airborne
Thamnidium where the temperature of the meat is raised to approximately 60Â° to
75Â° F in less than 8 hr; then held at temperatures of approximately 65Â° to 75Â°
F for 32 hr or more; and then reduced to approximately 32Â° to 35Â° F in less
than 8 hr.

During the meat-ripening cycle the relative humidity is maintained above
90% and up to 100% saturation including supersaturation for all or part of the
time cycle. During the cooling portion of the cycle the air in the meat-ripening
space is sterilized to kill or inhibit the growth of undesirable mold and
bacteria in the atmosphere.

During the
cycling of temperature described on the previous page, the air in the space
where the chilled meat is being ripened increases in temperature to
approximately 70Â° to 75Â° F in 4 hr or more and during the cooling cycle
decreases in temperature from approximately 70Â° to 75Â° F to approximately 33Â°
to 35Â° F in approximately 4 hr, more or less, depending upon the meat load or
volume of meat to volume of air space.

Thamnidium may be introduced both during the heating cycle of
approximately 8 hr and during the holding cycle of approximately 36 hr. The
presence of Thamnidium controls bacterial action even at the relatively high
temperatures. Thamnidium is introduced into the meat aging space as by spraying
in a glycerol suspension from an aerosol-type bomb. The same timing mechanism
that times the heading, holding and cooling cycle in the meat-ripening space may
also be employed to periodically actuate the atomizer for Thamnidium. Other
means for introducing Thamnidium into the meat-aging space can be employed.

In view of the relative shortness of time during which Thamnidium is
active in the processes, approximately 44 hr, practically no mold appears on the
surface of the meat since about 4 days are required for the hyphae or whiskers
of the mold to appear. However, the mycelia of the mold grow into the meat
during the entire cycle enhancing the flavour of the meat. Thamnidium, by
inhibiting bacterial activity which causes darkening of meat, actually
contributes to the brightening of the colour of the meat.

As noted above, during the cooling cycle of approximately 4 to 8 hr, the
atmosphere within the meat-ripening space is sterilized to destroy bacteria in
the atmosphere which are deleterious to the meat. This sterilizing action is
preferably continued until the end of the meat-ripening cycle, until removal of
the meat from the ripening space, and until the ripening space is again filled
with meat to be ripened. Thus, at the beginning of the ripening cycle, the air
in the ripening space is substantially sterile. Both mechanical means and /or
chemical sprays may be employed to sterilize the air in the ripening space
during the cooling cycle.

For example, electrostatic precipitation may be employed, and/or
propylene glycol or tributyltin oxide may be sprayed periodically in to the
ripening space. Here again, the timing mechanism employed to regulate the
meat-ripening cycle may be employed to periodically spray the chemical sprays
into the meat-ripening space during sterilization of the atmosphere, or may be
employed to actuate the electrostatic precipitator, or actuate combinations
thereof.

Pre-Rigor Mortis Injection Of Aspergillus Niger
Mycelium

Research and Development Company has discovered that the favour of meats
can be greatly enhanced with improvement in tenderness by the use of the
mycelium of the Aspergillus mold, particularly the Aspergillus niger used in
citric acid production process. The bland or green flavour of meat is converted
to an aged flavour without in any way detracting from other desirable qualities
of the meat.

The
appropriate time to inject the mycelium of Aspergillus niger into the carcass is
immediately after slaughter while the tissues are still fluid and flaccid and
before incipient rigor mortis. The amount of fluid containing the mycelium
injected into the carcass is preferably proportional to the normal moisture loss
during chilling of the meat being treated. It is known that carcass beef loses
approximately 1% of its natural moisture during the first 24 hr in the cooler
and another 1% during the next 5 to 7 days.

The quantity of fluid containing the mycelium should be equal to and not
less than the amount of moisture lost by the beef during ordinary commercial
practices. The fluid containing the mycelium serves to replace the moisture lost
by the beef during chilling and cold storage and the beef is not softened or
unduly moistened by addition of an amount of fluid equivalent to the amount of
moisture lost by the beef.

It is preferred to introduce the mycelium in its fluid or aqueous carrier
into the meat to be treated by injection. The fluid containing the mycelium is
introduced into the carcass through a hollow needle which is introduced into the
portions of the carcass to be treated at rather closely spaced intervals.

A representative eviscerated carcass of beef may weigh approximately 600
Ib and when divided into halves, each side will weigh approximately 300 Ib. such
a carcass will lose approximately 6 Ib of moisture initially or 3 Ib of moisture
for each side. Therefore a minimum of 3 Ib of the tendering fluid containing the
mycelium is used for each side and a maximum of up to 6 Ib of the fluid may be
employed. An average for such a side of beef is 4 Ib of the fluid containing the
mycelium.

The fluid is introduced by stitch pumping. The 4 Ib are distributed into
the half carcass by injecting approximately a pound of the fluid into the round;
another pound is pumped into the muscle of the loin; another pound is pumped
into the rib; and the remaining pound is pumped into the chuck and distributed
through the neck and front shank. This provides adequate distribution throughout
the entire carcass and results in uniform flavour enhancement of the beef.

After the meat has been treated in accordance with the process described
above it is chilled in the normal way and handled by conventional practice. When
the mycelium containing fluid is pumped into the meat there will be no trace of
the fluid since the warm, fluid, flaccid muscles before rigor mortis absorb and
distribute the fluid without trace. The mycelium of Aspergillus is sterilized to
kill any living organisms and is then dried and powdered before introduction
into solution and so does not require freezing or cooking to prevent
overflavoring of the meat. Meat exhibits enhanced aged flavour within a short
time after treatment of the carcass.

The fluid containing the mycelium of Aspergillus is introduced into the
warm carcass on the killing floor at a temperature approximating 118 F.
Carcasses of beef, lamb, veal, pork and other animals when first killed and
dressed have a normal body temperature of approximately or above 98.6Â° F. If
the fluid containing the mycelium is introduced into the meat at a temperature
above 98.6Â° F or normal animal body temperature, and below a temperature which
would cause searing or cooking of the meat, 120Â° to 125Â° F, the fluid will
elevate the body temperature of the normally dressed meat and will improve the
colour and appearance of the meat and will improve the colour and appearance of
the meat as well as activate the natural enzymes thus causing an improved and
accelerated aging and flavouring action.

The additional heat introduced by the fluid containing the mycelium and
heated to approximately 118Â°F has beneficial effect of keeping the carcass warm
for an hour or more of treating time, providing better distribution throughout
the carcass of the flavouring fluid.

Improvement of tenderness is probably mainly due to the action of water
injected under pressure. However, it probably can be partially attributed to the
action of mycelium of Aspergillus.

The mycelium of Aspergillus is readily obtainable. A number of processes
have been developed whereby a solution of sugars of various kinds is inoculated
with Aspergillus niger for the purpose of producing citric acid. A mat
consisting primarily of the mycelium of the fungus grows on top of the solution
and through reactions which are not thoroughly understood the sugars are
converted, to a greater or less extent, to citric acid. The efficacy of the
fungus falls off rapidly when it starts to sporulate.

When this occurs the mat is removed, placed in a filter press, and the
moisture, including the acid and remaining sugars, is expressed from it insofar
as possible. The mycelium mat is a waste product which is available in large
quantities. The mycelium mat may or may not be washed prior to the filtering in
order to remove as much as possible of the sugar and citric acid solution, but
whether it has been treated in this manner or not appears to make no difference
in the flavour of the resultant meat product.

The resultant mycelium mat or filter cake, which may be obtained in this
fashion, it then thoroughly dried and ground to the desired particle size. The
degree of grinding is largely a matter of choice. Fairly coarse particles may be
used or the mat may be completely pulverized. The preferred size of particle is
approximately the same as that of ordinary table salt, or such as facilitate
suspension and solution in the injection medium.

The ground,
dried mycelium may be mixed with a substantially equal amount, by weight, of
table salt (or other suitable taste or flavour additives), the two ingredients
being thoroughly mixed. The proportions are not at all critical, but the average
taste seems to be best met by equal proportions; enough of salt to taste the
meat with sufficient Aspergillus flavour to give the meat the required zest.

It is no necessary to include salt with the mycelium, except that it
might be helpful in preserving it while dry and is also not unbeneficial to the
meat. Salt has some tenderizing effect upon meat. The meat seems somewhat more
tender and juicy because of the hydroscopic properties of the salt in drawing
and holding moisture.

The amount of mycelium which produces best flavouring results in the
range of 0.05 to 0.2% of the weight of the carcass. Using 0.2 (600Ib beef), 19.2
oz or 540 g would be used per carcass. This is dissolved in an amount of
solution equal to about 1% of the carcass weight or about 6 pints of fluid per
carcass. Six pints of fluid equals 2,839 g containing 540 g of mycelium product,
or 18.10%. The amount of salt added to this is discretionary, but within the
limits, perhaps somewhat lower than is normally used on meat, so as to permit
additional salting during cooking or at the table, without
making the meat too salty.

Acid Activation of
Thamnidium Elegans

Research
and Development Company describes the discovery that the mold Thamnidium may be
used in the home to age and impart flavour to meat within a period of 12 to 48
hr. the elegans strain is one of the four better known strains and is
paiticularly efficacious for this process because of its activity at room or
home refrigerator temperatures, its hardiness and its stability.

The mold Thamnidium, when in contact with meat, readily propagates and
secretes a proteolytic enzyme. This mold, or more likely, the enzyme, functions
to age the meat and to improve the flavour, imparting to the meat the highly
desirable black walnut flavour and the accompanying rich, full flavour so well
known to connoisseurs. This action of the mold can be activated or accelerated
under room or home refrigeration conditions by the addition of an edible organic
acid such as citric acid or tartaric acid thereto. The elegans strain is
particularly desirable because it is psychrophilic or cold-loving and is
particularly active at room or home refrigerator temperatures (32Â° to 50Â° F).
It is rendered dormant at freezing temperatures and fails to grow at
temperatures around 75Â° F. It is killed at temperatures approaching 100Â°F or
above.

Referring to figure 1, the process is practiced by placing a cut of meat,
such as the steak 10, on a rack 11 supported on a tray 12 having a removable
cover 12, contained within the tray is the Thamnidium, which may be contained in
a generally rectangular pillow 13 consisting of a previous mildewproof fabric
cover 14, preferably of a material such as nylon or ramie netting, encasing an
absorbent base material 15. The base material, which is preferably sawdust,
shavings or, as shown, a cellulose sponge in particuiate form, is impregnated
with the mold Thamnidium, preferably organic acid.

The amount of acid is not especially critical but should be maintained
within the range of 1 to 10% based on the weight of mold used. The allow is
preferably provided at one end with a pair or strings 16 for conventence in
maintaining the pillow in the rolled from the storage, as shown in figre 1c and
1d.

In certain aspects the Thamnidium with edible acid may be absorbed in
sawdust alone. Thamnidium may be cultured on a clear plastic base, provided with
a suitable potato dextrose agar for growth of the mold and this assembly provide
in the pillow under the absorbent base material. Alternatively and preferably,
the mold is prepared in a suspension which is absorbed by the absorbent base
material. Preferably, the citric or other organic acid in the form of a powder
is sprinkled on the base.

The Thamnidium-impregnated base is most conveniently marked by wrapping
it in a suitable moisture proof, relight covering, soon as ellophane (not
shown), upon which is imprinted complete directions for use by the boutendor.
Upon removal of the wrapping, exposing the base to the air, the base is hundred
with one teaspoon of water in order to dissolve the citrisied and thus â€¦mold.

The base is then put into the try, as shown and the entire assembly
covered and left at room temperature or placed in the refrigerator. Thamnidium,
being airborne, will rise and contact the surface of the uncovered meat. Saing
protostele, the mold will have no affability for anything in the refrigerator
except the meat. The mycelia will grow into the meat thus imparting the aged
flavour and to some extant, tending to improve the tenderness and palarability
of the meat. Preferably the meet is turned over once during me treatment period,
which should perform 12 to 48 hr. Depending upon how much aged flavour is
desired for the particular cut of must.

After use of the impregnated base it is best to store it in the moisture
proof sirtignt wrapping at room temperature. The effectiveness of the base may
last for many months and through many reuses. It stored in the freezer it will
gradually lose its effectiveness. Six months storage at 0Â°F killed off 80% of
the Thamnidium spores.

Example: Two identical unaged steaks, I thick were cut from a strictly
fresh beef loin, A base as generally described before was prepared by thoroughly
dampening the base, white ping sawduer, with a suspension of Thamnidium
containing % by weight of citric acid. The culture had been grown on slants of
pomtodextrose-agar and spores and bits of the hyphae were used to produce a
heavy luxuriant growth. A suspension, in 25% solution of glycerol in sterile
distilled water to which was added the % of citric acid, was made.

One of the steaks was placed on the rack several inches above the
mold-containing base and the assemble was covered and placed in the refrigerator
in an area maintained at about 40Â° F. The other or second steak was placed in a
different refrigerator so as to avoid any contact by Thamnidium. The first steak
was turned once during the treatment period of about 48 hours, so as to expose
both sides to the direct airborne action of the moid.

Following this treatment, both steaks were cooked and sampled. Before
cooking, it was observed that the second (untreated) steak had the normal poor
appearance of meat held for two days in the refrigerator, i.e. it had large
areas of gray rixed with the red, indicating the usual bacterial contamination.
This steak has a rather old odor. The first (treated) steak was of a deep, rich,
red, uniform colour with no noticeable bacterial contamination are with a
well-aged odor i.e., the characteristic black walnut odor noticed when a
well-aged loins e.g., hung for 21 to 35 days at 34Â°F is first opened up.

In comparing the cooked steaks, it was observed that the untreated steak,
although good, was somewhat bland, whereas the treated steak seemed more tender,
tasted like a much better piece of meat and had a rich, full- bodied flavour,
all the characteristics of four or five weeks of aging.

Anta-Mortem
Injection or Thamnidium and Aspergillus

If controlled amounts of Thamnidium and Aspergillus are injected into a
living livestock animal in a physiological saline colution, thase live, active,
viable organisms are distributed throughout the meat by the vascular system of
the animal. After injection the livestock animal may be held alive for up to
about 41 hour and then slaughtered. The carcass is then chilled and neld in a
cooler for aging, that is, to permit the development of the mold spores within
one tissues of one meat.

Hodges Research and Development Company has discovered that the retail
cuts of meat from the carcass will show uniform improvement both in tenderness
and in flavour. The Thamnidium injected into the living animal. Producers a
delectable aged flavour in re meat the Aspergillus injected into the living
animal, working synergistically with the Thamnidium, produces greatly improved
tenderness in the meat.

The mold species belonging to the Thamnidium alegans and Aspergillus
oryzae groups are preferred in this process because these organisms are
nonpathogenic and will grow and elaborate the desired proteases in standard
media and transplants will grow and flourish under ordinary laboratory
procedures. Furthermore, Thamnidium and Aspergillus spores are both
psychrophilic or cold-loving and are therefore able to carry out their functions
of flavouring and tenderizing the cold meat at the temperature range in the
usual cooler of 34Â° to 40Â°F.

The amount of Thamnidium and Aspergilus to be injected into the livestock
animal may vary from 500 to 1,000 spores total of these molds per milliliter of
the animalâ€™s blood. Assuming that an average beef cattle has 10 liters of
blood, the physiological aline injected coluion should contain from 5,000,000 to
10,000,000 spores total of these molds. These molds are usually used in equal
amounts in the solution but variations from this ratio may be used.

It should be kept in mind that the Thamnidium mold contributes more to
flavour than to tenderness while the Aspergillus mold contributes more to the
tenderness of the meat than to its flavour. The satine solution is preferably of
sterile distilled water having an isotonic salinity of approximately 0.8% NacI.
Approximately 50 ml of the saline solution containing these molds is vascularly
injected into the average beef cattle at 5 ml for each liter of blood.

Example: A.
U.S. Good grade beef steer weighing approximately 1,050 1b and producing a 600
1b beef carcass consisting of two split, dressed sides of 300 1b each was
injected with an isotonic blood-level temperature sline solution containing
approximately 5 million.

Viable spores each of the molds Thanmidium elegans and Aspergillus
oryzae. The live animal was restrained and an incision made in the jugular vein
to permit the bloodstream to accept the alien solutions. Without difficulty,
over a period of about 5 min, the entire 50 milliliters of solution was injected
and gravity drained into the jugular vein and thereafter circulated throughout
the vascular system to the venules, capillaries and arterioles of the flesh of
the animal. Approximately 30 min after the injection, the animal was slaughtered
and dressed in the usual manner and the two sides of beef were placed in a
regular cooler for conventional chilling.

As a control for the process, a similar steer of like age and weight from
the same feederâ€™s lot was selected, held and slaughtered immediately following
the treated steer. The two cattle were held in the same cooler under identical
conditions for 10 days. Comparable steaks and roasts were cut from comparable
sides of each beef at 2,5 and 10 day periods, rated for appearance, colour and
other visual characteristics, then cooked similarly and compared
organoleptically by a panel of meat experts. In all cases, the panel preferred
the treated meat and rated it higher on their score cards both for tenderness
and flavour. The improvement in flavour was more significant than the
improvement in tenderness although tests made on a Warner-Bratzler shear machine
of cylinders of meat cooked to 155Â°F indicated less resistance and therefore
more tenderness for the treated meat.

CHAPTER
7

PRESERVATION
: MOISTURE RETENTION AND SURFACE PROTECTION

A serious concern of the meat industry is the control of surface
deterioration and shrinkage which results in large monetary loss. In the aging
of beef, for example, excessive surface dehydration of the carcass or primal
cuts makes it necessary to trim away the deteriorated outer portions in order to
place the meat in a salable form.

Frozen meats are subject to a condition known as â€œfreezer burnâ€.
Frozen meat, when unprotected by a suitable packaging material, develop an
objectionable surface texture and off-colour due to surface dehydration. There
are methods of meat processing which limit the amount of moisture lost from the
meat and protect the surface of fresh meats.

LONG
CHAIN HYDROCARBON COATING

The preservation of the surface properties and the reduction of shrinkage
of fresh meat involves several problems. Obviously, moisture evaporation must be
prevented. Furthermore, the material used in this connection should permit the
passage of atmospheric oxygen in order to maintain the meat surface pigments in
oxygenated form. Hence, the material should be moisture-impermeable and, at the
same time, sufficiently airpermeable. Long chain hydrocarbons seem to form a
suitable coating which provides a barrier for reducing moisture loss.

Fatty Alcohol or Fatty Acid Protective Film

This process relates to an improved manner of handling meats, including
carcass meat, primal cuts and other fresh meats, to reduce shrinkage
attributable to the loss of moisture and to lessen freezer burn in frozen meats.

Swift & Company discovered that the holding of meat coated with a
thin film of a fatty compound having the formula R-OH or R-COOH, where R is
selected from the group consisting of an aliphatic radical or an acyl radical
having from 11 to 12 carbon atoms or with a thin film of ethyl stearate will
reduce the moisture loss normally experienced in the handling of the meat. The
film of the long chain fatty compound is believed to be monomolecular in
thickness and may be conveniently formed by the application of an aqueous
dispersion of the compound to the meat surface preferably by spraying.

The
aqueous dispersion is preferably an emulsion of the fatty material in water
although the aqueous dispersion may be prepared by dissolving the fatty material
in the water with the aid of a common solvent, such as ethyl alcohol. The use of
the aqueous dispersion is important to the successful application of the
material to form an air-permeable moisture-retarding barrier. The suitable
materials are waxy, crystalline flakes or needles of high melting points which
cannot be satisfactorily applied to the meat, except through an aqueous
dispersion, to form the necessary monomolecular film.

The fatty alcohols and fatty acids of the foregoing formula vary
considerably in their effectiveness in this process. Among the preferred
materials are the fatty acids and alcohols having from to 16 to 20 carbon atoms
inclusive and mixtures of those materials. The C10 to C20 materials
will generally be found to provide the greatest resistance to water evaporation.
Particularly suitable compounds include octadecanol, hexadecanol (commonly known
as cetyl alcohol), stearic acid (octadecanoic acid), and arachidic acid
(eicosanoic acid) as well as the ester ethyl stearate. The saturated alcohols
and acids are usually more effective than the unsaturated materials of like
carbon number; for instance, stearic acid is preferred to oleic acid.

Other fatty acids that may be employed include lauric, tridecylic,
myristic, palmitic, margaric acids and the higher fatty acids such as the C20
and C22 fatty acids. The corresponding alcohols for example,
dodecanol tridecanol etc. may be used but generally the fatty acids and
alcohols, below the C16 to C20 carbon range are less
effective than those of that preferred range. Dodecanol for example offers a
relatively low resistance to moisture evaporation, being less than about
one-sixth as effective as cetyl alcohol. Hexadecanol and octadecanol are
particularly desirable materials and may be expected to reduce shrinkage from 30
to 70% of that experienced in their absence. Arachidic acid is also a
particularly effective material.

The fatty material forms a thin invisible film on the surface of the meat
which is permeable to air thus permitting the maintenance of the bloom on red
meat. The material does not adversely affect the protein or fat of the meat nor
does it impart an objectionable surface texture. The fatty compounds are readily
applied with little labor and their use lessens the need for expensive humidity
adjusting equipment. However, the process may be used in comunction with the
maintenance of a high humidity, thereby still further reducing shrinkage loss.
The fatty material in the amount needed is inexpensive and is generally
effective at the temperatures at which meat is commonly held.

The aqueous emulsion may be prepared in the following manner. Equal
weights of cetyl alcohol (hexadecanol) for example, and any of certain edible
emulsifying agents are mixed together, after first heating both the emulsifying
agents and the cetyl alcohol to a temperature in excess of 49Â°C. The warm
mixture is then agitated with water in a mechanical shaker or a blender until
the cetyl alcohol is placed in aqueous emulsion. In an alternative, the
emulsifier may be added to the warm water and then heated cetyl alcohol
introduced and the mixture shaken to form the emulsion. There are many
emulsifiers suitable for use, among these are the edible partial fatty esters of
polyhydric alcohols, including propylene glycol and glycerol.

The suitable emulsifiers include monoglycerides, diglycerides and
mixtures thereof. A preferred emulsifier contains approximately 40%
monoglyceride, 40% diglyceride and 20% triglyceride. An esterified mixture of
lactic acid and glycerol may also be employed.

It is possible to prepare an aqueous emulsion without the aid of an
emulsifier. In this instance, the cetyl alcohol or other material is added to
water at an elevated temperature of about 90Â°C, and the mixture violently
shaken or stirred. This will yield an emulsion, which will be suitable until the
temperature reaches approximately 50Â°C; hence the emulsion should be sprayed
immediately or the meat dipped before the temperature has dropped. It is
recommended, when using such an emulsion, that a fine orifice spray not be
employed. A colloidal mill may be advantageously used for the preparation of the
stable emulsion.

The fatty acid alcohol, or ethyl stearate may be applied in water
dispersions of remarkably low concentrations. These materials when applied to
the meat surface in a dispersed water phase have the ability of forming an
apparently continuous monomolecular film. Concentrations of 50 to 1,000 parts of
the fatty material per million (ppm) of water have been profitably employed.
However, emulsions of greater and less concentrations may be used with varying
degrees of effectiveness.

Example, 1: Fatty mg of cetyl alcohol (hexadecanol) was dissolved in 1 ml
of ethyl alcohol and the solution stirred into 1 liter of water having a
temperature of approximately 70Â°C. Two pieces of beef from the same primal cut
were obtained and one was dipped into the aqueous solution. The other piece was
used as a control. The results of this experiment with the weights at 0, 24 and
48 hours. The treated sample had a fully acceptable colour and texture. No
effort was made to adjust the humidity of the refrigerated room.

Example 2: A ewe carcass was split in half and one-half was sprayed with
75 ml of 50 ppm of an aqeous cetyl alcohol emulsion. Much excess liquid drained
off of the carcass. The emulsifier used was a 40-40-20 mixture of mono-,di-, and
triglycerides. The refrigerated space has a low humidity.

There was no difference in colour between the two sides of the split
carcass and the meat in all respects presented an acceptable appearance. Aqueous
octadecanol or arachidic acid emulsion as well as ethyl stearate emulsions will
provide comparable protection. In each instance the emulsion can be prepared as
described in either example 1 or example 2.

Example 3: The work of this example demonstrates the advantage to be had
in the use of cetyl alcohol in connection with frozen meat. Frozen meats
frequently exhibit an objectionable off-colour and texture described as freezer
burn. Two pieces of beef, unfrozen, were selected and one piece was dipped in a
40-ppm aqueous emulsion of cetyl alcohol. The two samples were placed in an open
display retail type freezer and held at 0Â° F for 72 hours and at the end of
that period the control sample had a freezer burn of a degree that would have
made it unsalable. The cetyl alcohol treated meat had an acceptable appearance
and evidenced a pronounced improvement in colour and texture of the meat surface
over the control sample. It is recommended that the aqueous emulsions be applied
to the meat before freezing.

Preliminary Ice Coating

T.R. Anderson; has found that the usefulness of the fatty film on frozen
meat may be improved by first coating the meat with ice and then forming the
moisture retarding fatty film on that ice. It is believed that the fatty film,
when used on frozen meat, to be effective, or at least to be most efficient,
requires the continued existence of an ice layer intermediately disposed of the
meat and the fatty film itself.

An ice
layer is seemingly necessary for the proper alignment or orientation of the
fatty molecules making up the monomolecular film. By first coating the meat with
ice and then forming the fatty film, there is provided a considerable reserve of
water needed for prolonging the effectiveness of the film. Where the fatty film
has been formed by the simple application of an aqueous dispersion of the fatty
material to the meat (without first forming an ice coating) the underlying ice
is apparently made up of the water of the originally applied aqueous dispersion
and the monomolecular film then becomes much less effective in retarding
sublimation of moisture from the meat.

The ice glaze or coating may be formed by either spraying or dipping of
the meat in water. In the instance where the ice coating is a lamination of ice
layers, the lamination is built up through the multiple applications of water
with each application followed by a freezing before the meat is again dipped or
sprayed. In some instances, it may be profitable to freeze a block of ice around
the meat.

Moisture loss from frozen meat may adversely affect its quality. Freezer
burn caused by intense local drying in cold storage results in an objectionable
whitened and wrinkled condition. With prolonged storage the drying may extend to
the interior so that the flesh becomes loose and inelastic. The process will
greatly reduce shrinkage and freezer burn.

The moisture-retarding film is formed of a saturated aliphatic compounds
having the formula R-OH, R-COOH, where R is an aliphatic radical having at least
11 carbon atoms. Ethyl stearate may also be used.
The fatty compound may be applied in the form of an aqueous dispersion,
for example, an emulsion of the fatty material in water. The aqueous dispersion
may be prepared by dissolving the fatty material in the water with the aid of a
readily volatile solvent, such as ethyl alcohol. The suitable materials are, for
the most part, waxy, crystalline flakes or needles of high melting points which
cannot be satisfactorily applied to the meat, except through a dispersion, to
form the necessary thin film.

The fatty acid, alcohol or ethyl stearate may be applied in water
dispersion of remarkably low concentrations. Concentrations of 30 to 1,000 parts
of the fatty material per million (ppm) of water have profitably been employed.
However, dispersions of greater and less concentrations may be employed
depending on the particular material used. The coating procedure with a fatty
film is fully described by Anderson in U.S. Patent 2,948,623 previously
discussed.

Intermediate Glycerol Layer

Film-forming
fatty materials such as cetyl alcohol (hexadecanol), arachidic acid and
octa-decanol form a thin film, believed to be monomolecular in thickness, on
meat which significantly slows the loss of moisture from the meat. The film
forming material is applied to the meat through an aqueous dispersion.

T.R. Anderson; has found that the fatty film may be formed through the
application of a glycerol dispersion of the fatty material to the meat surface.
Preferably, the application is achieved with the use of a glycerol-water
dispersion (25 to 50% volume glycerol concentration) of the film-forming
material. The dispersion may be prepared through the use of an emulsifier
or of a readily volatile solvent, such as ethyl alcohol.

The presence of the glycerol on the surface of the meat is also thought
to serve a useful purpose in maintaining the molecules of the fatty film in the
proper orientation necessary to the continued effective existence of the film.
The film formed by the fatty material on meat is believed to be monomolecular in
thickness and to depend upon the presence of an intermediate layer (between the
meat and fatty film) of polar material, e.g., water for its existence.

The various fatty materials, suitable for use in the formation of the
moisture-retarding film, each possess a polar group in their configuration of
atoms; for example, hexadecanol has an OH (hydroxyl) group at the end of a
16-carbon atom chain. The polar group is hydrophilic. The carbon chain being
hydrophobic is repelled by water. The results is an alignment of the fatty film
molecules, with the polar groups of the fatty molecules being attracted
to the water (of the intermediate layer) and with the long carbon chains
standing on end more or less perpendicular to the water surface and closely
packed. The closely packed, erect fatty molecules retard the escape of water
vapor from the water surface (and hence from the meat) so long as the molecules
are aligned and compressed together.

The following is offered as a possible explanation of the process.
Glycerol is suitable for use as the material of the intermediate layer (disposed
between the meat and fatty film) because of its three hydroxyl groups and low
vapor pressure. Glycerol has solubility characteristics similar to water and may
be substituted in whole or in part for the water in the intermediate layer. The
presence of the several hydroxyl groups in glycerol attract the polar groups of
the various film-forming fatty materials and repel the long carbon chains of
those compounds.

In shorts, the film-farming materials act towards glycerol as they do
towards water, forming a moisture-retarding film. The low vapor pressure of
glycerol assures the continued existence of the intermediate layer to support
the fatty film in turn is thought to reduce still further glycerolâ€™s low vapor
pressure. The glycerol or glycerol-water oriented fatty film will suppress
moisture evaporation from a meat carcass as does the water oriented film.

Glycerol has been commonly employed in a great variety of uses in
connection with food. In fact, physiologically, it is a food, nontoxic and
easily digested. It has a sweet taste and possesses little or no odor. In one
embodiment of the process the meat is first coated with glycerol or preferably a
glycerol water solution. An aqueous dispersion of the hexadecanol or other
suitable fatty material is then applied to the glycerol coated meat to form the
thin moisture-retarding film.

The moisture-retarding film is formed of a saturated aliphatic aliphatic
radical having the formula R-OH or R-COOH, where R is an aliphatic radical
having at least 11 carbon atoms. Ethyl stearate may also be used. The fatty
compound may be applied in the form of a glycerol dispersion, for example, an
emulsion of the fatty material in glycerol or glycerol and water. The glycerol
dispersion may be prepared by dissolving the fatty material in the glycerol (or
glycerol and water) with the aid of a readily volatile solvent, such as ethyl
alcohol.

The fatty acid, alcohol or ethyl stearate may be applied in dispersion of
remarkably low concentrations. Concentrations of 30 to 1,000 parts of the fatty
material per million (ppm) of water and glycerol (or glycerol alone) may be
profitably used. However, dispersions of greater and less concentrations may be
employed, depending on the particular material used.
The glycerol because of its high viscosity is preferably used in water
solution. Water-glycerol solutions of varying concentrations may be employed.
The detailed coating procedure with a fatty film has been previously described.

Example: Small chunks of stew beef were used in this experiment. The
several chunks after treatment were refrigerated at 36Â°F. Sample No. 1 had no
treatment at all. Sample No. 2 was dipped in water and Sample No. 3 was immersed
in a 50 to 50% glycerol-water solution and drained. Sample No. 4 was treated
with an aqueous dispersion of cetyl alcohol (500 ppm). Sample No. 5 was dipped
in a cetyl alcohol (500 ppm) dispersion of water and glycerol (50 to 50%
solution).

It will be seen from the following table that the glycerol and water
treatment (no cetyl alcohol) Sample No. 3 was ineffective in reducing shrinkage,
providing no more protection than the water dip of Sample No. 2. However, when
used with a small amount of cetyl alcohol (Sample No. 5) the treatment reduced
shrinkage significantly.

Intermediate
Water Layer

Film-forming fatty materials such as cetyl alcohol (hexadecanol)
arachidic acid, and octa-decanol form a thin film on meat, which significantly
slows the loss of moisture from the treated meat. It appears that in time this
moisture retarding film becomes less efficient, if not ineffective, when applied
to chilled meat normally held in a dry state.

T.R. Anderson, has discovered that the effectiveness of the film toward
moisture evaporation may be improved by supplying water to the treated meat in a
mist, for example, through a heavy fog containing discrete particles of water or
in a fine spray. Fortuitously, water introduced in this fashion to the treated
meat does not permanently damage the monomolecular film. The film parts to
permit the passage of the water particles there through and after wards,
reforms. The fatty film, so to speak, is self-healing.

The following is offered as a possible explanation of the improved
process. It is thought that the effectiveness of the hexadecanol or other fatty
film depends upon the continued presence of an intermediate water layer between
the monomolecular fatty film and the meat. The water of this intermediately
disposed film is believed to be initially made up of water from the originally
applied aqueous dispersion. Early in the refrigeration of the treated meat the
moisture lost from the underlying water layer through the fatty film to the air
is replaced by the free water of the meat; however, after a period of time the
free water does not transfer to the water layer at the required rate and as a
result in time the molecules of the fatty material making up the monomolecular
film become randomly distributed with the result that the film loses its
effectiveness.

The supply of the sprayed water to the intermediately disposed water
layer is thought to continue the existence of the molecules of the overlying
fatty film in the proper orientation necessary to the life of an effective film.

First a fatty film is applied to the meat (as previously described in
U.S. Patent 2,948,623). The sprayed water is preferably supplied intermittently
to the treated meat during its refrigeration. The frequency of application is
regulated to supply that amount of water needed to assure the existence of the
properly oriented fatty film. A particularly suitable apparatus for developing
the water laden mist is the fogger described. For a large scale operation, a
large number of the Kofford foggers will be required and they may be
conveniently provided with a time control for intermittent operation if desired.

The greatest rate of moisture loss occurs during the cooling of the
recently killed carcass from its body temperature to that of the refrigerator.
The intermittent application of the mist during the early hours of refrigeration
supplies the needed water to replenish that lost by evaporation from the water
layer underlying the fatty film itself. Without the water furnished by the mist,
the moisture required to continue the existence of the underlying water lying layer (and of the fatty film itself) would have to be
supplied by the free water of the carcass.

Example: Twelve recently slaughtered carcass were divided into four lots
of three each. Lots A and B were dipped in an aqueous dispersion of hexadecanol
(concentration of 60 ppm). Lots C and D were dipped in water containing no film
forming material. Lots A and C were hung in a first compartment of a
refrigerated space maintained at 3Â° C. This compartment was provided with a
fogger (mist forming apparatus). The other two lots (lots B and D) were hung in
a second compartment (isolated from the first) of the same refrigerated space.
No mist was supplied to the second compartment. Lots A and C were subjected to
five minutes of mist every hour interval throughout a test period of eight
hours.

The results demonstrate clearly the advantage to be had in supplying the
sprayed water to the treated meat.

Lactic
Acid-Fatty Acid Triglycerides

Freeze-dried meats under normal storage conditions are subject to
nonenzymatic deterioration, resulting in loss of colour and the development of
bitter flavour and off-odors. The products also have an affinity for moisture
under these conditions. The development of new packaging materials and methods
have been found to be helpful in delaying the rapid loss in quality of
dehydrated foods under storage but are by no means 3 complete answer to the
problem. For example, freeze-dried beef packaged in aluminium
foil-paper-polyethylene pouches, and placed in storage at 70Â° F has a
satisfactory quality life of only 3 to 5 days.

In
order to protect the quality of freeze-dried meats, Armour and Company propose
the use of a coating composition. Although this coating composition consists
predominately of meat fat, and although it is applied to the exterior surfaces
of the freeze-dried meat, the coated meat can be rehydrated without difficulty,
using water at room temperature or below.

The coating composition employed is composed principally of lard and beef
tallow in admixture with a minor proportion of a mixed lactic acid-fatty acid
triglyceride. It is preferred to employ triglycerides which are formed from
lactic acid and at least predominately from fatty acids containing from 14 to 18
carbon atoms. The triglycerides may contain from 1 to 2 mols of fatty acid, and
from 1 to 2 mols of lactic acid. Mixtures of such triglycerides can also be
used. A typical triglyceride is glycerol lacto palmitate. Glycerol lacto
stearate can also be used, or mixture of the palmitate and stearate.

In one typical embodiment, the coating composition contains from 20 to
40% by weight of lard, from 50 to 70% of beef tallow, and from 5 to 20% of the
mixed triglycerides. Somewhat improved results can be obtained by also
incorporating in the composition from 1 to 10% by weight of a vegetable oil,
such as soybean oil, cottonseed oil, or other normally liquid vegetable oil.

The coating is applied to the dehydrated meat, which may be beef, pork,
lamb, etc. after the meat has been subjected to a freeze-drying procedure, and
preferably as soon after freeze-drying procedure is not critical.

It is preferred to apply the coating by spraying. Coatings will liquefy
within the temperature range from 75Â° to 100Â°F. In other words, at
temperatures below 75Â°F, the composition will be substantially solid, while at
temperatures of 100Â°F or above, the coating will be in the form of a flowable
liquid. Consequently, to facilitate the application, the coating will be applied
at a temperature within the range from 125Â° to 175Â° F would usually prove
acceptable.

The principal requirements are that the coating composition be liquefied
sufficiently to permit it to be sprayed and applied as a thin even coating,
while at the same time not being at such a high temperature that it denatures or
otherwise changes the character of the surface of the meat. For precooked
freeze-dried meats, somewhat higher temperatures can be used without
disadvantage than with freeze-dried fresh meats. However, the process is
applicable to both fresh and cooked freeze-dried meats.

The configuration of freeze-dried meats is usually that of
relatively thin slices so that the external surface area of the meat is
relatively large compared to the volume. It is usually not necessary, however,
to employ more than 1 part of the coating composition per 10 parts by weight of
meat. In most applications, the desirable proportion will range from 4 to 8
parts by weight of the coating composition per 100 parts of the meat. Any large
excesses of the coating composition should be avoided.

Example: One-fourth inch slices were cut from U.S. Canner Cutter bottom
rounds and freeze-dried. After drying, the slices were cubed (1/2â€x Â½â€ x Â¼â€),
sifted, and placed into polyethylene bags under nitrogen.

Treated cubes were sprayed with an emulsion mixture of 1 part of oleo oil
(90% lard-10% soybean oil), 2 parts of deodorized beef tallow and 3/10 part of
GLP (glycerol lacto palmitate) at the rate of 5 to 7% by weight of the meat
product and at spray temperature of 160Â°F. the temperature of the meat product
was approximately that of room temperature. The spray application was made as
evenly as possible to all surfaces by constant mild agitation of the cubes
during spraying. The mixture solidified immediately upon contact with the meat
product. Samples of freeze-dried beef, not subjected to the treatment, served as
the control.

After this preparation, two ounces of control and treated cubes were
placed into laminated cans and sealed with 0,15â€, or 28â€ vacuum. These were
stored at 40Â°, 70Â°, and 100Â°F for 0, 15, 30, and 60 days. At each sampling
period, objective analyses were conducted. The results of this experiment
indicated that the increase in moisture content during storage of the
freeze-dried beef treated with the coating mixture was substantially reduced
irrespective of vacuum or storage temperature. Moreover, the degree of moisture
increase from 0 to 60 days storage was less for the treated samples.

CHAPTER
10

OTHER
METHODS OF PRESERVATION

DEHYDRATION
METHODS

Solvent Dehydration

The
process developed by J.E. Thompson; wherein the solvent dehydration is effected
without heating and within the range of ordinary room temperature, can be
carried out with substantially unspecialized apparatus. Losses of solvent in the
process, due to evaporation, are held to a minimum. Further the products
obtained are readily rehydratable, and when reconstituted not only retain the
desirable characteristic original flavour to a marked degree, but also exhibit
satisfactory texture and consistency, or mouth feel. Fresh meats can be treated
successfully by the process.

A solvent is employed which has the capacity to absorb water from the
meat tissues, and which readily may be separated from the processed meat
material after treatment. This solvent is nontoxic or sufficiently nontoxic that
any minute residues that may be retained in the dehydrated meat can have no
toxic effect when ingested into the human system, and further, exerts a specific
antiseptic action on the meat during processing.

When ethanol is used as the solvent it not only fulfills the foregoing
condition but has the advantage of being selective with respect to the fat
content of the meat material, in that it is not only a good dehydrating agent,
but also, in sufficient concentrations has the capacity to dissolve fatty
material. According, if it is desired to defeat the meat, as well as dehydrate
it, the water content of the ethanol should be a minimum, whereas if it is
desired to dehydrate only, a higher water content could be present. The
dissolved fat may be readily separated from the alcohol by addition of water.
Likewise the degree of dehydration can be regulated by adjustment of the
proportion of water in the ethanol, a concentrated solution acting as a strong
dehydrating agent, and a weak aqueous solution of ethanol having a minimum
dehydrating action.

Additionally, ethanol is an efficient bactericide and when used in the
process has the beneficial effect of destroying microorganisms that are present
in meat. Moreover, ethyl alcohol leaves no toxic residue in the final product.
Ordinarily it is found satisfactory to use a standard denatured ethyl and
alcohol 95.2%.

The separation of the spent solvent from the treated material may be
effected by settling and decantation, filtration, and centrifugal separation.
Thereafter the dehydrated residual meat product may be dried at atmospheric
temperatures to remove remaining solvent. The separated solvent which will have
taken up water from the meat material may be recovered for reuse by simple
distillation or if desired, by azeotropic distillation. Fat, separated from the
meat material, may be recovered in the supernatent layer of the spent solution.
Where ethyl alcohol is used, separation of fat is induced by the presence of the
dissolved water. If necessary the separation of the fat from the solvent may be
brought about by further dilution with water.

The solvent extraction apparatus is illustrated in figure 1. A, 1b and C
represent vessels wherein the solvent actions are effected. Each of these
vessels is provided with closures a, b and c, respectively, to prevent
evaporation of the liquid contents. M1, M2 and M3 indicate a batch of meat material during each of the 3 stages
of processing. S1 S2 and S3 indicate the
solvent which is used successively
in vessels in vessels A, B and C. spent solvent is trans ferred from vessel C to
distillation, the overhead being returned to supply source11 and thence to
vessel A wherein the meat material M3 undergoes its final extraction.
The watery liquids from the comparatively small losses of solvent during the
course of the process, fresh solvent may be introduced as needed into the supply
source.

In operation as illustrated, meat in a suitable state of subdivision is
first introduced into vessel C wherein it is subjected to a relatively mild
extraction with partially spent solvent S3. Thereafter the meat is
separated from the liquid in vessel C by decantation and filtering, and
transferred into vessel B wherein it is subjected to a stronger treatment with
extracting solvent S2. Following this the partially dehydrated meat
is transferred into vessel A where it is exposed to the action of the solvent in
its most concentrated form. The processed meat is now ready after draining to be
dried at room temperature. During the 3 stages of treatment, the meat is
subjected in all to an amount of solvent equal to approximately 9 times the
volume of the meat. The meat undergoes a marked shrinkage in volume. The total
weight loss is about two-thirds of the initial weight as moisture and some fat.

Example: Fresh pork tissue was cut into pieces approximately 1â€ sq and
Â½â€ thick, placed in a vessel with special denatured ethyl alcohol (formula
SDA-3A), and permitted to stand for a period of time sufficient to dissolve
substantially as much water as the solvent would take up. The liquid was then
drained off and the extracted material treated successively with fresh alcohol.
It was found by this treatment that the lean tissue was very considerably
reduced in volume, whereas the effect on the fat was comparatively small. By
cutting away from the material
initially the majority of its visible fat, a pork product was obtained which was
suitable for use in preparing various cooked dishes.

With regard to the time for treating the samples in a 3-stage extraction
process, equilibrium is reached in 4 to 24 hours, satisfactory results having
been obtained at the end of 4 hours. The dehydrated samples absorbed water so as
to be reconstituted taking up approximately 90% of the water removed and hold
this water so as to give a product that is edible and may be used in the place
of fresh meat. For example 1 lb of dehydrated products from which 3 lb of water
had been removed could be soaked in water to restore the original approximate 4
lb weight. It was found that a final moisture content of 6 to 12% of the protein
content of the final product kept quite well without refrigeration for several
weeks. For indefinite longer storage the moisture content should be reduced to
approximately 2%.

Drying Without Case Hardening

Case hardening is a problem confronting the manufacturer of dried foods
and is especially acute in the field of meat drying. For example, when fresh
meat is dried directly in hot air the surface dries first, thereby interfering
with subsequent evaporation of moisture from the interior of the meat. This
surface drying or case hardening produces a meat product which is often gummy in
texture and which has very poor rehydration properties. For example, the
appearance, texture and palatability of a rehydrated, case-hardened product are
less than desirable and the rehydrated products is often not equal in weight to
the initial fresh product due to its inability to readily absorb moisture
through the hardened surface.

J.L. Shank; has provided a method for drying fresh meat without
developing case hardening and with improved rehydration properties. By
impregnating fresh meat with a minor amount of an edible colloid prior to
drying, the meat may thereafter be dried directly in hot air without developing
case hardening. Moreover, the product formed has excellent flavour and texture
characteristics and, in some instances, almost doubles its weight or
reconstitution with liquid. The
meat may be impregnated with colloid by cooking it in a dilute solution of the
colloid for a time sufficient to impregnate it with the desired amount of
colloid.

The minor amount of colloid which is impregnated in the meat is
sufficient to coat each surface film or fiber area with a film of the colloid
through which moisture diffuses during the hot air drying. This colloidal film
prevents excessive desiccation of the meat surface itself thereby preventing
case hardening and insuring easy reconstitution when the meat is rehydrated. The
colloidal film also facilitates the departure of moisture from the meat so as to
produce a desiccated product having a substantially uniform moisture content
throughout. Preferably the meat to be dried is sliced to develop thin sheets or
strips; for example, sheets 1/8â€ to Â¼â€ thick are especially suitable.
Thicker sheets or slices are operable, particularly up to about Â½â€ to Â¾â€
thick, but of course length of time in the drier is correspondingly increased.

A convenient method of preparing the slices of meat is to first
soft-freeze the meat to give it body and minimize juice loss during slicing and
then cut sheets of the desired size and â€“shape. Thinner slices of meat, e.g.,
down to about 1/16â€, may be prepared but the resulting dried product will be
quite fragile, and of course the thinner the slice the less acute the problem of
case hardening. The sheets, strips or chunks are then cooked in a dilute
solution of edible colloid. We have found that a cooked in solution containing
about 1% colloid will completely prevent case completely prevent case hardening
and can be advantageously employed to substantially always give a definite
decrease in case hardening and an increased rehydration ratio.

Greater amounts of colloid up to about 6% or more, for example, can be
used and will prevent case hardening and have excellent rehydration properties.
However, when the concentration of colloid increases above about 2% the colloid
content of the dried product rises above about 10% (weight basis), which of
course cuts down the protein content of the dried meat. Thus, the upper level of
colloid may be governed by the upper level of colloid tolerable in the final
product. It has been found that about 2% colloid is the optimum level for good
rehydration characteristics.

The cook solution may also contain flavouring ingredients, for example,
salt. If, for example, salt is added in the cook solution, loss of natural salt
from the fresh meat is substantially prevented. It will, therefore, be apparent
that by controlling the salt content a low-salt dried meat can be produced.
Low-salt content products are in demand for dietary purposes. The major amount
of the cook solution is water, although several batches of meat may be cooked in
the same solution so that some meat juices, solids, etc. may be present in
addition to the colloid and any added flvouring ingredients. The amount of
solution per unit weight of meat is not particularly important, it being
necessary only that the resultant broth not be too thick or too watery.

Generally, about twice as much water as meat (weight basis) produces a
very suitable solution. The colloids that are useful are the edible film
formers. Examples include, but are not limited to, gelatin, starch and gum such
as agar, locust gum, Arabic pectins, gum Irish moss, gum tragacanth, etc. the
cooking time and temperature may be varied depending on the colloid used. For
example if gelatin is used, the cooking temperature is preferably reduced to
about 120Â° to 125Â°F.

After the cooking operation which may involve about 1 to 2 hours cooking
at 200Â° to 212Â°F (or lower temperatures, especially if gelatin is used), the
meat pieces are removed from the cook solution and deposited on a surface for
drying. Drying screens are especially suitable. It will be noted that as the
colloid solidifies the meat pieces tend to adhere to the surface. The screen can
be placed in a hot air drier. Generally, time and temperature vary inversely in
the drying operation, temperatures above 160Â° F hasten drying and temperatures
of 190Â° to 220Â°F being optimum for meat drying. Humidity control in the ovens
is not required.

The meat pieces are removed from the ovens when dry and may be packaged,
if desired. Generally, the oven drying will be complete in 45 minutes to 3
hours. The time will be dependent on the desired moisture content. In this
process the meat is considered dry when its moisture content falls between about
1 and about 7%. The dried meat thus prepared will be substantially free from
case hardening and will have a rehydration ratio greater than one and in many
cases (particularly if the optimum amount of colloid is employed) about 1.8 or
1.9%.

Initial
peroxide ME/K
3-6

Rehydration
ratio
1.8-1.9

pH
5.7-6.1

Example: 1:A quantity of beef was soft-frozen, sliced in sheets about
%â€ thick and aliquot portions were cooked for 1.5 hours at about 200Â°F in
water containing varying amounts of agar from 0.5 to 5.9%. A control cook was
also run. The meat pieces were removed from the cooking solutions placed on
screens and dried in a hot forced-air drier maintained at 190Â° to 200Â°F. After
about 2 hours when the moisture content was reduced to less than 5%, the meat
was removed from the drier. The following comparative table gives the analysis
of the products.

The dried meat containing 1% or more agar in the cook solution showed no
case hardening. The meat made with 0.5% agar was not completely free form case
hardening, but was not unsatisfactory from an organoleptic standpoint and had
better rehydration properties than the control. The control meat exhibited case
hardening sufficient to be an undersirable product.

Example2: Beef pieces were cooked for 2 hours in an aqueous solution
containing 1% salt and 5% gelatin. The cook temperature was maintained at 120Â°
to 125Â°F. The meat was separated from the broth and dried at 160Â° F. The
product was dry in 2 to 3 hours and exhibited no case hardening.

Example 3: Strips of thin beef were cooked for about 2 hours in an
aqueous solution containing 0.5%, weight basis, gum Irish moss. The cook
temperature was 212Â°F.
After cooking the beef was separated from the broth and dried at 160Â° to 200Â°F.
The product was dry in 45 minutes to 1 hour. No case hardening was exhibited.

Example 4: A batch of dried beef was prepared by the method of example 3
except that 0.5% gum tragacanth was substituted for the gum Irish moss. The
product was free from case hardening and exhibited good rehydration properties.

PRESERVATION
OF FLAVOUR

Antioxidant Application To Freeze-Dried Meats

Freeze-dried fat-containing meats become excessively rancid on exposure
to atmospheric conditions within about 24 hours. Freeze-dried meats should
therefore be protected from such exposure in order to protect them from
spoilage. Borden, inc. provide a method for treating freeze-dried fat-containing
meats with an antioxidant which effectively prevents the oxidation reaction from
proceeding when such meats are exposed to atmospheric conditions. Treatment with
the antioxidants extends its storage life considerably.

The method comprises fat-containing freeze-dried meat sprayed with at
least 250 parts of an edible antioxidant for 1 million parts of fat which is
meant to result in a freeze-dried meat product containing about 200 parts of
antioxidant for 1 million parts of fat. This amount of antioxidant will prevent
the meat at room temperature under atmospheric conditions from spoiling for at
least 30 days.

The antioxidants used are of the hydroxy phenyl derivative class.
Examples include butylated hydroxyanisole, and propyl gallate. The antioxidants
may be used separately or in combination and in further combination with
chelating agents such as citric acid and salts of ethylenediaminetetraacetic
acid. The preferred combination is butylated hydroxyanisole and citric acid. The
process is carried out by spraying the antioxidant composition onto freeze-dried
meat in an inert atmosphere.

Freeze-dried meat, containing about 2% of moisture, is placed in a
rotating and tumbling inducing apparatus such as for example what is
conventionally called a pill coaler. The atmosphere prior to addition of the
freeze-dried meat may be purged with an invert gas such as nitrogen or carbon
dioxide. An antioxidant composition is then added as by spraying in the form of
a fine mist onto the surface of the rotating and tumbling freeze-dried meat. The
propellant generally used in the spraying operation is an invert gas, for
example nitrogen or carbon dioxide. After treatment with the antioxidant the
freeze-dried meat may be packaged in an inert gas (e.g., nitrogen) for use in
commerce.

By spraying the antioxidant composition via an inert atmosphere onto a
freeze-dried product which is continually tumbling and rotating the product is
uniformly treated with the desired amount of antioxidant. As applied it does not
absorb excessive liquid in local areas which would result in a soggy product. It
is preferred to introduce the antioxidant composition (liquid) into the tumbling
and rotating freeze-dried product at a rat not to exceed about 2 fl oz/hr/Ib of
freeze-dried product. Generally the composition is sprayed at the rate of
between about 0.5 and 1.5 fl oz/hr/Ib. The amount of inert gas carrier is
not critical other than the economic limitation on excessive quantities and
ineffective spray techniques with less than minimum amounts.

In general, about 150 to 500 parts by weight of antioxidant added, per
million parts by weight of fat content, results in a usable product. Generally
about 300 ppm will give storage life period in excess of 34 days. The preferred
range is 200 to 300 ppm. A chelating agent may be admixed with the antioxidant
in proportion in the range of up to 55 parts for 100 parts by weight of
antioxidant composition consists essentially of an admixture of 100 parts by
weight of butylated bydroxyanisole, 15 to 25 parts by weight of citric acid and
propylene glycol in an invert carrier atmosphere of nitrogen or carbon dioxide.
Where the storage temperature is in excess of room temperature storage life is
decreased for a given amount of active antioxidant agent.

Deodorization of Raw meat

R. McCarthy, the former assigned to EEFP Corporation has provided a
method for the removal of the undesirable flavour and spoilage-influencing
substances from animal meat prior to final preservation (e.g., by canning,
freezing, radiation treatment, etc.).

Raw animal meat, cut into pieces, is placed into open-top containers.
Each container is then moved from the filling station to a high pressure and
subcook heating station where the temperature of the meat and the pressure in
the container are both raised, preferably by injecting steam from a steam source
through the open top of the container directly into the meat while at the same
time confining at least some of the steam and the vapors and gases from the
meat, evolved as a result of the heating, in the container. After a suitable
amount of time, the heating is discontinued and the pressure on the meat is
reduced to atmospheric pressure by releasing the steam and evolved vapors and
gases from the container.

The heat, pressure and sudden reduction of pressure all act to break down
meat tissues and remove the barriers which they offer to the escape of flavour
and spoilage influencing substances which are sealed in the meat cells and
tissues. Next, the meat is moved to a low-pressure and extraction station and
while still hot, is subjected to a vacuum. The pressure in the container is
lowered to a value substantially below atmospheric pressure. This creates a
pressure differential across the tissues of the meat since the liquids in the
meat are still at or slightly above atmospheric pressure. As a result, these
liquids, which are still hot, boil and the vapors and gases evolve from the meat
tissues.

The container is at least partially inverted when connected to the vacuum
source so the substantially all of the loose liquids and free vapors and gases
are removed or extracted from the meat and removed from the container. Finally
the container and its contents are moved for preservation, as by canning,
freezing, radiation treatment, etc. The preserved meat product is then ready for
future use as a source of food.

In figure 2 an open-top metal can C containing raw meat is shown
supported on a pad 30 below the outlet end of a steam injection head 32. The
steam injection head comprises concentrically arranged inner and outer
frustoconical walls 34, 36 respectively, forming a central steam chamber 38 and
an annular exhaust chamber 40 surrounding the steam chamber. The inlet end of
the steam chamber is communicated through a three-way valve 42 with either
conduit means 18 leading from the steam source 16 or vent passageway 20 leading
to the atmosphere, by automatic movement of the valve plug 44.

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